1. Field of the Invention
The present invention relates to an improvement of a scroll type compressor which can be used, for example, in an air-conditioning system of a vehicle such as an automobile.
2. Description of the Related Art
For example, Japanese Unexamined Utility Model Publication No. 60-125382 discloses a scroll type compressor for an air-conditioning system of an automobile, which comprises immovable and movable scroll members housed in a housing and having spiral guide walls engaged with each other in such a manner that spaces are formed as a compression chamber therebetween. The movable scroll member is revolved around a central axis of the immovable scroll member in such a manner that an engagement is maintained between the spiral guide walls of the immovable and movable scroll members, and that the spaces or compression chambers therebetween are displaced toward the central axis of the immovable scroll member.
During the revolution of the movable scroll member around the central axis of the immovable scroll member, a compression chamber appears successively at the outermost portions of the spiral guide walls thereof, and opens to take in a refrigerant fed from an evaporator of the air-conditioning system, and then the compression chamber concerned is fully closed by the spiral guide walls, due to the revolution of the movable scroll member. Thereafter, as the compression chamber concerned is displaced toward the central axis of the immovable scroll member, a volume thereof becomes gradually smaller, whereby the refrigerant confined therein is compressed, and when the compression chamber concerned reaches the central axis of the immovable scroll member, the compressed refrigerant is discharged through a reed valve into a discharge chamber formed in the housing of the compressor. After the discharge of the compressed refrigerant into the discharge chamber is completed, the compression chamber concerned disappears at the central axis of the immovable scroll member, and thus a compression of the refrigerant is successively carried out.
A spiral space defined by the spiral guide wall of the immovable scroll member is in communication with the suction chamber through an inlet passage provided at the outermost zone of the spiral space at which a compression chamber successively appears during the revolution of the movable scroll member, whereby the refrigerant can be effectively introduced from the suction chamber into the compression chamber while the latter opens. Nevertheless, conventionally, the effective introduction of the refrigerant into the compression chamber cannot be completely carried out.
In particular, the immovable and movable spiral guide walls are engaged with each other in such a manner that the outermost zone of the spiral space defined by the immovable spiral guide wall is divided into an inner section and an outer section by the outermost portion of the movable spiral guide wall, and the inner and outer sections are alternatively displaced as a compression chamber toward the central axis of the immovable scroll member during the revolution of the movable scroll member around the central axis of the immovable scroll member. An inlet port of the inner section for feeding the refrigerant thereto is defined by a termination of the outermost portion of the movable spiral guide wall, and said termination is disengaged from and engaged with the immovable spiral guide wall during the revolution of the movable scroll member around the central axis of the immovable scroll member to close and open the inlet port of the inner section. In this case, the inner section cannot be fed with a sufficient amount of refrigerant, because the inlet port of the inner section is restricted and closed by the termination of the outermost portion of the movable spiral guide wall, and because a part of the refrigerant introduced from the suction chamber into the outermost zone of the spiral space through the inlet passage is directed to the outer section.